Boom supported aerial buckets, of the type having a peripheral flange, are widely used in many industries and are most extensively used in the power and utility industries where it is frequently necessary to provide mobile access to power lines and other electrical facilities. In using such aerial buckets repairmen are exposed to risk of serious injury, and it is generally recognized that facilities must be provided for the immediate emergency treatment of an injured repairman. Whereas the boom can usually be lowered to bring the bucket to ground level, it may be extremely difficult to lift the person from the bucket, particularly if the person is unconscious or otherwise incapacitated.
Numerous attempts have been made to deal with this problem, the commonest being based on the use of a block and tackle mounted on the boom itself whereby the injured repairman may be simply lifted from the bucket. This has a number of drawbacks, one being that the lifting system must first be moved into the operative position, which means that the hydraulic system of the aerial device must remain fully operative after the accident has occurred. Another drawback is that a lift assembly permanently mounted on the device adds to its weight, while also making it difficult or impossible to keep the boom clear as it must for high voltage work. Then again, a permanently mounted lift assembly is subject to deterioration through continual exposure, making it unreliable when needed.
On the other hand, in the case of a separate lift assembly to be mounted on the ground, ground features such as ditches, rocks, etc. may limit access to the bucket on one or more sides.